No external dimmers were involved. As I wrote, I opened up a bulb myself (sawed off the tip of the base) and saw electronic parts consistent with a switch mode

No external dimmers were involved. As I wrote, I opened up a bulb myself (sawed off the tip of the base) and saw electronic parts consistent with a switch mode power supply (dozens of parts including rectifier, capacitor, tiny transformer, rectifier, capacitor, IC for controlling it). I know I saw something different than was in the video for the UK version! No reason China can't produce both.